Some electronic filter assemblies used for multi-phase electric currents include transformers, inductors, and the like. These assemblies can include vertically oriented and parallel ferrite limbs joined by horizontally oriented and parallel ferrite yokes. Conductive wires are wound around the vertical limbs to form the assemblies. During operation, electric current is conducted by some of these windings to induce magnetic flux in the ferrite limbs and yokes. This flux can be conducted through the yokes to other limbs, where the flux can induce another current in the wires. This other current can be a current that is filtered or otherwise transformed by the assembly before being conducted to one or more loads.
Due to the vertical orientation of the limbs, these types of filter assemblies may not be magnetically symmetric. For example, different magnetic fluxes induced in different limbs may be conducted different distances and/or along different paths. This can cause an uneven temperature or heating distribution in the limbs and yokes, which may lead to decreased service life or damage to the filter assemblies. Additionally, because the yokes typically are relatively large in order to be coupled with the limbs, the filter assemblies may be large and heavy.
The asymmetric filter assemblies also can cause significant increases in impedance and/or leakage of magnetic flux from the assemblies during common mode operation. For example, when the asymmetric filter assemblies are used to conduct a common mode magnetic flux, the common mode flux may not be able to be conducted through the yokes to the other limbs. As a result, impedance of the filter assemblies increase significantly and/or the common mode flux leaks from the limbs and yokes of the filter assemblies.